Janet, G., Widmeyer, E., D. (2001). Infants, toddlers and caregivers ed.5 (Ed. 5). : Myfielsd Publishing.

Gonzalez-Mena, Janet., Eyer, Dianne, Widmeyer. "Infants, toddlers and caregivers ed.5". Ed. 5 : Myfielsd Publishing, 2001. Textbook.